Streaming - A Practical Guide to Video and Audio Compression - page 351

20.7.1 Managing the Risk by Buying a Service Instead of Running Your Own

Other alternatives are available to purchase, and there is also a business model built by
Akamai and Kasenna around the concept of a streaming service. They add significant
value to the proposition because of their infrastructure. Refer to the discussion about edge
servers in Section 20.12.

20.8 Areas of Difficulty and Streaming Tricks

Because the design of the Internet is not optimized to support streaming services, tech-
nology implementers need to be ever more inventive when trying to extract the maximum
performance from the available network capacity.

20.8.1 Hinting

Hinting is a process that is applied to files after they have been compressed. It adds time-
coded annotations on a separate track, which the streaming server can use to optimize its
performance.
There are several common hinting mechanisms described by standards bodies as
well as proprietary schemes developed by manufacturers:
You should consult your streaming-server documentation to find out what kind of
hinting is required and how to include it in your files. The open standards are likely to be
more widely supported, and products such as the Popwire encoders will insert the non-
proprietary hints as part of the compression process.

20.8.2 Buffering

Because of the generally unreliable way that packets arrive across the Internet with respect
to their sequencing and timeliness, streaming players will buffer a certain amount of

Table 20-1 Hinting Strategies

Format Status

IETF Open standard

ISMA Open standard

3GPP Open standard

QuickTime Proprietary

Real Networks Proprietary

Windows Media Proprietary

Vara Wirecast: http://www.varasoftware.com/